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Algae/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby A man, Tim, and a robot, Moby, are sitting in a row boat on a pond. Lots of green vegetation is visible in and around the water. TIM: Man, it’s hot. A close-up of Tim shows he is sweating. TIM: Ooh, nice! Tim sees that Moby is holding an umbrella and an envelope. MOBY: Beep. TIM: Dear Tim and Moby, what are those little green plants that cover ponds in the spring and summer? From H. I. Tim opens and reads a letter. TIM: You’re probably talking about algae. A green blob floats by in the water. TIM: Algae are not plants, though. They’re plant-like organisms, but they don’t have roots, stems, or leaves like real plants do. TIM: Most algae are eukaryotic, meaning their cells have nuclei. A view through a microscope shows individual algae cells connected in long chains. Each chain is two cells wide, and long enough to extend out of view in both directions. Each cell contains a spring-shaped feature and one small round object. One of the round objects in a cell is labeled “nucleus”. Text reads: Spirogyra s p. MOBY: Beep? TIM: Algae cells contain a green pigment called chlorophyll. The spring-shaped features in the algae cells flash, and the label “chloroplast” appears pointing to one of the spring-shaped features. TIM: Chlorophyll lets them create their own food through photosynthesis, just like a plant. The screen splits up and down. In the upper half, a sun is emitting light rays illustrated by wavy yellow lines. The light rays strike a green blob on the water’s surface. The lower half of the screen shows the microscopic view of the algae cells. The sun rays enter this scene and terminate at chloroplasts. TIM: Because photosynthesis produces oxygen, algae are an important source of the air we breathe. Tiny algae called phytoplankton form the basis of most saltwater food chains. A view through a microscope shows a variety of phytoplankton. There are many shapes and their colors include red, brown, and green. TIM: It’s safe to say that without algae, the world would be a much tougher place to live. MOBY: Beep? TIM: Algae are divided into a bunch of different categories, including green algae, which is the most common type, with thousands of different species. As Tim begins speaking, a table of algae categories is shown. An amorphous green blob Text reads: green algae A dark red branched structure Text reads: red algae Brown, leaf-shaped structures Text reads: brown algae A smooth, green tubular structure with cord-like features coming out of one end Text reads: euglenoids A yellow, oval shaped structure with ridged features Text reads: diatoms A red polyhedron shaped roughly like a ball, with cord-like features coming out of one end Text reads: dinoflagellates TIM: It may not look like much, but almost half of our oxygen comes from green algae. Tim reaches out of the boat and picks up some of the green blob from the pond. TIM: Red algae have chlorophyll in their cells, but they have a red pigment too, which helps them absorb sunlight from deep in the ocean, where many of them live. A dark underwater scene shows an example of red algae, which is a macroscopic branched structure, growing from the ocean floor. TIM: Most brown algae live in the ocean too, and include different types of seaweed and kelp. Brown algae stalks are shown growing from the ocean floor. Each stock is a long leafy structure waving in the current. Two fish swim up and appear to be eating one of the brown algae stalks. TIM: You may be eating red and brown algae without even realizing it! Tim is sitting in the boat. TIM: Carrageenan, a substance found in red algae, makes everything from pudding to toothpaste nice and smooth. A box of pudding mix and a tube of toothpaste are shown. TIM: Red, green, and brown algae include both single- and many-celled species. But euglenoids, diatoms, and dinoflagellates, are all single-celled. The table of algae categories is shown again. An amorphous green blob Text reads: green algae A dark red branched structure Text reads: red algae Brown, leaf-shaped structures Text reads: brown algae A smooth, green tubular structure with cord-like features coming out of one end Text reads: euglenoids A yellow, oval shaped structure with ridged features Text reads: diatoms A red polyhedron shaped roughly like a ball, with cord-like features coming out of one end Text reads: dinoflagellates TIM: Some of these organisms are pretty weird. Euglenoids often have animal-like features, including whip-like flagella and eyespots that are sensitive to light. A diagram of a euglenoid is shown moving through the water. It is a single, elongated cell with multiple dark green, amorphous features and a nucleus inside. A cord-like structure coming out the back of the cell is labelled “flagellum”. There are two round features in the cell near where the flagellum originates, one of which is labeled “eye spot.” TIM: The cell walls of diatoms, or gold-brown algae, are rich in silica, the main element in glass. A series of yellow objects suspended in water is shown. They are a variety of shapes but most gave some symmetry and some hard edges. They sparkle in the light. TIM: And dinoflagellates have special flagella that make them spin in circles. A dinoflagellate is moving through the water. It is a red, round cell. It has a flagellum in the back that seems to be propelling it forward, and a second flagellum attached on the side that makes the overall spin of the cell apparent. MOBY: Beep? Moby frowns. TIM: Right, dinoflagellates are responsible for red tide. A sandy beach is shown. The water close to shore is colored red, and transitions to blue farther away. TIM: That’s when they cover the surface of the sea and discolor it. An inset shows that a microscopic view of the red portion of the water contains numerous red dinoflagellates. TIM: Algal blooms like red tide can cover huge areas of water and devastate ecosystems. MOBY: Beep? Moby is still frowning. TIM: Well, a bloom can block out the sunlight from other organisms and deplete oxygen levels in the water. A shallow underwater scene is shown. There is a layer of dark red at the top of the water. Despite the bright visible sky above the water, the water under the red layer, as well as the sea floor, is dark. A lone fish swims along. Tim: And some algae actually secrete poisons into the water. The fish dies abruptly, flipping over and sinking to the bottom. MOBY: Beep? Moby is smiling. TIM: That’s right, there’s another interesting type of algae called cyanobacteria. Once called blue-green algae, cyanobacteria are single-celled organisms that may actually not be algae at all! Cyanobacteria are shown in the water. Each cell is capsule -shaped and has no apparent features except an outside border. The cells are blue. TIM: Cyanobacteria are prokaryotic, which means they don’t have a cell nucleus. In fact, they don’t have any cell organelles whatsoever! A close-up of one of the cyanobacterial cells is shown. In the close-up, it has a number of visible features with a variety of shapes, sizes, and colors. One of the features, a smooth round object, disappears after Tim explains there is no cell nucleus. The remaining features disappear in sequence after Tim explains there are no cell organelles whatsoever. Eventually, the cell resembles those in the previous diagram, with nothing visible except an outside border defining the shape. TIM: Because of that, scientists think that cyanobacteria are more related to bacteria than algae. Like algae, though, cyanobacteria in water habitats can form blooms that release harmful toxins. Tim is facing the screen while talking. Then Moby is shown frowning and looking down at the water with all of the green blobs floating around. MOBY: Beep, beep? TIM: Well no, no, I don’t think this is an algal bloom. MOBY: Beep, beep, beep! Moby begins to pull on the oars and the boat begins to move through the water. TIM: I really…I really don’t think we have anything to worry about. The boat tips side to side as it moves out of view. After it is out of view, a loud splashing sound is heard. TIM: Well, now look what you’ve gone and done. The boat is mostly underwater and the umbrella is floating on the surface. Tim and Moby rise up from underwater, covered in the green algae. Tim spits a chunk of algae out of his mouth.Category:BrainPOP Transcripts